Field of the Invention
The present invention relates to a coil component and a manufacturing method of the coil component, and particularly to a coil component that uses a drum core and a manufacturing method thereof.
Description of Related Art
In recent years, electronic components that are used in information terminal devices such as smartphones have been strongly required to be smaller in size and lower in height. Therefore, as for coil components such as pulse transformers, surface-mount coil components that use drum cores instead of toroidal cores have been frequently used. For example, Japanese Patent Application Laid-Open No. 2012-119568 discloses a step-up transformer of a surface-mount type that uses a drum core.
The coil components that use drum cores have been required to be even smaller in size and lower in height. The size of a winding core portion has been decreasing from year to year. In order to secure a required inductance, a coated conductive wire that is thinner in diameter needs to be used.
However, the coated conductive wire that is thin in diameter is low in dielectric strength voltage. Accordingly, coil components that need to insulate primary and secondary windings, such as pulse transformers, may be insufficient in dielectric strength voltage. In particular, if wires are connected to terminal electrodes by thereto-compression bonding or laser bonding, heat that is applied at the time of wire connection is conveyed via core material of the coated conductive wire, and the coating film would be degraded. Therefore, the problem is that the component is likely to be insufficient in dielectric strength voltage.